Assembly line structure

ABSTRACT

An assembly line for assembling a product by a series of operations comprises a conveyer body assembly which includes a plurality of conveyer body units. Each unit has an assembly area for carrying out a predetermined process for producing a product to be assembled and forms a minimal unit which takes charge of a part of the series of operations. The conveyer body assembly is formed by connecting an arbitrary number of conveyer body units greater than or equal to two, which makes it possible to cope with any change in the production plan or the like with a high flexibility.

FIELD OF THE INVENTION

The present invention generally relates to assembly line structures, andmore particularly to an assembly line structure which can cope with achange or modification in the production plan and the like with a highflexibility.

BACKGROUND OF THE INVENTION

The workload and the number of processes required to assemble a productdiffer depending on the product. For this reason, it is desirable thatthe assembly line has a structure such that the assembly operation caneasily be changed.

FIG. 1 shows an example of a conventional line. In FIG. 1, an assemblyline 1 includes a conveyer body part 1a having a total length L₁ whichis set to a length corresponding to the operation order which isinitially planned for the product to be assembled, and traverse parts 1band 1c which are integrally formed on a starting end and a finishing endof this conveyer body part 1a. An assembly area part 1a-1 and a palletreturn conveyer part 1a-2 are arranged in parallel in the conveyer bodypart 1a. 2-1 through 2-n denote operators, and a pallet 3 which is anassembly jig is transported as indicated by an arrow 4.

There are cases where the product being assembled is changed due to achange in the production plan or the like. In such cases, no particularproblem occurs if the number of processes required to assemble the newproduct is smaller than the number of processes required to assemble theproduct of the initial production plan. However, if the number of theprocesses is greater, there is a problem in that the existing assemblyline 1 cannot be used. SUMMARY OF THE INVENTION

Accordingly, it is a general object of the present invention to providea novel and useful assembly line structure in which the problemdescribed above is eliminated.

This and other objects of the present invention are attained by anassembly line for assembling a product by a series of operations,comprising a conveyer body unit which has at least an assembly area forcarrying out a predetermined process with respect to the product to beassembled and forms a minimum unit which takes charge of a part of theseries of operations, and a conveyer body assembly which is formed byconnecting an arbitrary number of conveyer body units greater than orequal to two.

According to the present invention, the length of the assembly line canbe changed arbitrarily because the conveyer body assembly is formed bythe conveyer body units, and it is possible to cope with the change inthe number of processes, the change in the product to be assembled andthe like with a high flexibility. In addition, the cost of equipment canbe reduced because it copes with the change in the production plan orthe like by appropriately changing the existing assembly line, withouthaving to set up a new assembly line from the beginning.

Other objects and further features of the present invention will beapparent from the following detailed description when read inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram showing an embodiment of a conventional assemblyline;

FIG. 2 is a diagram illustrating the principle of a present invention;

FIG. 3 is a diagram for explaining the change in an assembly linestructure;

FIG. 4 is a front view showing an embodiment of the assembly linestructure according to the present invention;

FIG. 5 is a cross sectional view along a line V--V in FIG. 4;

FIG. 6 is a front view of one conveyer body unit in FIG. 4;

FIG. 7 is a diagram showing a transport surface of one conveyer bodyunit of FIG. 6;

FIG. 8 is a left side view showing one conveyer body unit of FIG. 6;

FIG. 9 is a partial enlarged cross sectional view along a line IX--IX inFIG. 7;

FIG. 10 is a front view of a starting end traverse unit of the assemblyline of FIG. 4;

FIG. 11 is a plan view of the unit shown in FIG. 10;

FIG. 12 is a left side view of the unit shown in FIG. 10;

FIG. 13 is a front view showing a finishing end traverse unit of theassembly line of FIG. 4;

FIG. 14 is a plan view of the unit shown in FIG. 13;

FIG. 15 is a right side view of the unit shown in FIG. 13; and

FIG. 16 is a cross sectional view showing another embodiment of theassembly line structure according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

First, the principle of the present invention will be described inconjunction with FIG. 2. In FIG. 2, any conveyer body unit 12-i of units21-1 to 12-n includes an assembly area part 12-ia on which an assemblyjig 11 is transported, and an assembly jig return conveyer part 12-ibwhich is arranged in parallel to and in correspondence with the assemblyarea part 12-ia (where i=1, 2, . . . , n). A starting end traverse unit13 is a independent from the conveyer body unit 12-i and transports theassembly jig 11 from the assembly jig return conveyer part 12-ib to theassembly area part 12-ia. A finishing end traverse unit 14 is a bodyindependent from the conveyer body unit 12-i and transports the assemblyjig 11 from the assembly area part 12-ia to the assembly jig returnconveyer part 12-ib.

An assembly line structure 10 is formed by arranging in line andconnecting a plurality of conveyer body units 12-1 through 12-n in anarbitrary number greater than or equal to two depending on the number ofoperation processes for assembling the product, and by respectivelyconnecting the starting end traverse unit 13 and the finishing endtraverse unit 14 at the starting end and the finishing end of thearbitrary number of conveyer body units which are connected. FIG. 2shows a case where two conveyer body units 12-1 and 12-2 are connectedto form a conveyer body assembly 15, and the conveyer body assembly 15in this case has a length L₂. However, the length of the conveyer bodyassembly 15 may be changed freely depending on the number of conveyerbody units used.

In the present specification, a "conveyer body unit" represents aminimal unit which is in charge of a part of the series of operations tobe realized by the assembly line structure. Accordingly, the operationto be carried out by one conveyer body unit may be related to one or aplurality of processes or, related to a part of one or a plurality ofprocesses. In addition, the number of operators who carry out theoperation at one conveyer body unit may be one or more.

A description will be given of an example of a case where the length L₂of the conveyer body assembly 15 is changed to L₃, by referring to FIG.3. The finishing end traverse unit 14 is removed, and one conveyer bodyunit 12-3 is connected to one conveyer body unit 12-2 at the finishingend of the existing conveyer body assembly 15, in line with the conveyerbody assembly 15, so as to form a conveyer body assembly 15A which hasthe length L₃ which is increased by the length of one conveyer body unit12-3. Thereafter, as shown in (C) of FIG. 3, the finishing end traverseunit 14 is set up and connected to the finishing end of the conveyerbody assembly 15A, so as to form an assembly line structure 10A.

Next, a description will be given of an embodiment of the assembly linestructure according to the present invention, by referring to FIGS. 4and 5. In FIGS. 4 and 5, those parts which are the same as thosecorresponding parts in FIGS. 2 and 3 are designated by the samereference numerals, and a description thereof will be omitted.

In the assembly line 10, the conveyer body unit 12-1 and the conveyerbody unit 12-2 are connected to each other by a bolt 20 in a linearlyarranged state to form the conveyer body assembly 15. The starting endtraverse unit 13 is fixed to the starting end of this conveyer bodyassembly 15 by a bolt 21, and the finishing end traverse unit 14 isfixed to the finishing end of the conveyer body assembly 15 by a bolt22.

The conveyer body unit 12-1 has a structure shown in FIGS. 6 through 9.The conveyer body unit 12-2 has the same structure as the conveyer bodyunit 12-1, and an illustration and description thereof will be omitted.

As shown in FIG. 6-9, the conveyer body unit 12-1 has a length l suchthat four operators 23-1 through 23-4 can carry out the operations. Thislength l may be reduced so that only two operators carry out theoperations at the conveyer body unit 12-1. For example, one operator isin charge of the operation related to one process.

A screw hole 24 for connection is provided at one end of the conveyerbody unit 12-1, and a metal fitting 25 for connection is provided at theother end.

A rail 26 for manual feeding is provided at the assembly area part12-1a, and a free flow conveyer 27 is provided at the assembly jigreturn conveyer part 12-1b. A motor 37 which drives the free flowconveyer 27 is mounted within the conveyer body unit 12-1.

Reference numeral 28 represents an assembly jig fixing stopper, 29represents a power source outlet, 30 represents a pressure coupler, 31represents a wrist strap connector for the operator, 32 represents anauxiliary shelf, 33 denotes an exhaust fan, 34 represents a board forholding drawings, 35 denotes a fluorescent lamp, and 36 represents amain exhaust duct.

FIGS. 10 through 12 show the starting end traverse unit 13 shown in FIG.4.

This traverse unit 13 is a body independent from the conveyer body unit12-1 and is mounted with a connecting metal fitting 40. In addition, aconveyer 41 with an elevator mechanism and a motor 42 for driving thisconveyer 41 are assembled in the traverse unit 13.

FIGS. 13 through 15 show the finishing end traverse unit 24 shown inFIG. 4.

This traverse unit 14 is a body independent from the conveyer body unit12-1 and is provided with a connecting screw hole 50. In addition, aconveyer 51 with an elevator mechanism and a motor 52 for driving thisconveyer 51 are assembled in the traverse unit 14.

Returning now to FIGS. 4 and 5, the conveyer body units 12-1 and 12-2are arranged linearly and connected by inserting the bolt 20 through thehole in the metal fitting 25 of the conveyer body unit 12-1 and thescrew hole 24 in the conveyer body unit 12-2 and tightening this bolt20. The two conveyer body units 12-1 and 12-2 which are connected inthis manner form the conveyer body assembly 15.

The starting end traverse unit 13 is connected to the starting end ofthe conveyer body assembly 15 by the bolt 21 which fixes the connectingmetal fitting 40 to the conveyer body unit 12-1 end of the conveyer bodyassembly 15. On the other hand, the finishing end traverse unit 14 isconnected to the finishing end of the conveyer body assembly 15, thatis, the conveyer body unit 12-2 end, by inserting the bolt 22 throughthe hole in the connecting metal fitting of the conveyer body unit 12-2and a screw hole 50 shown in FIG. 13 and tightening this bolt 22.

Accordingly, the assembly line structure 10 which is suited for theassembling operation of the product having eight operation processes isformed.

In FIG. 5, the assembly jig 11 is successively transported on theassembly area parts 12-1a and 12-2a of the conveyer body assembly 15 tothe right as indicated by arrows 60. When the assembly jig 11 reachesthe finishing end of the assembly area part 12-2a, the assembly jig 11is transported from the assembly area part 12-2a to the assembly jigreturn conveyer part 12-2b by the finishing end traverse unit 14 asindicated by an arrow 61 in FIG. 15, so as to traverse the conveyer bodyassembly 15. Next, the assembly jig 11 is successively transported onthe assembly jig return conveyer parts 12-2b and 12-1b of the conveyerbody assembly 15 to the left as indicated by arrows 62. When theassembly jig 11 reaches the finishing end of the assembly jig returnconveyer part 12-1b, the assembly jig 11 is transported from theconveyer part 12-1b to the assembly area part 12-1a by the starting endtraverse unit 13 as indicated by an arrow 63 in FIG. 5 and FIG. 12, soas to traverse the conveyer body assembly 15, and the assembly jig 11 isreturned to the original position.

The part or product which is assembled in the conveyer body assembly 15may be completed at the assembly area parts 12-1a and 12-2a or,completed after passing through the assembly area parts 12-1a and 12-2aa plurality of times. In the case where the part or product is completedafter passing through the assembly area parts 12-1a and 12-2a aplurality of times, the incomplete part or product is of coursetransported to the assembly jig return conveyer part 12-2b by thefinishing end traverse unit 14, together with the assembly jig 11, whenthe incompleted part or product reaches the finishing end of theassembly area part 12-2a. The completed part or product is manuallymoved to a predetermined rack or the like from the assembly area part12-2a.

Next, a description will be given of the formation of the assembly linestructure for the case where the product to be assembled changes, thenumber of operation processes increases by four, for example, and theproduct which requires twelve operation processes is to be assembled.

In this case, the assembly line is changed as described above inconjunction with FIG. 3. More particularly, in FIGS. 4 and 5, the bolt22 is removed, and the finishing end traverse unit 14 is disconnectedfrom the conveyer body assembly 15. In addition, another conveyer bodyunit 12-3 is connected to the conveyer assembly 15 by a bolt, and thefinishing end traverse unit 14 is connected to this conveyer body unit12-3 by a bolt.

Accordingly, the assembly line structure 10 is modified into an assemblyline structure 10A which is suited for assembling the product whichrequires twelve operation processes.

On the other hand, if the number of operation processes decreases as aresult of the change in the product to be assembled, one or a pluralityof conveyer body units are removed to reduce the length of the assemblyline.

FIG. 16 shows another embodiment of the assembly line structureaccording to the present invention. In FIG. 16, those parts which arethe same as those corresponding parts in FIG. 5 are designated by thesame reference numerals, and a description thereof will be omitted.

In this embodiment, a plurality of conveyer body assemblies 15₁ through15_(n) are arranged approximately in parallel to each other andconnected to the traverse units 13 and 14. The assembly line structurecan be modified similarly as in the case of the above describedembodiment, by inserting or removing the same number of conveyer bodyunits in each of the conveyer body assemblies 15₁ through 15_(n).

In each of the above embodiments, the term assembly is intended for theoperations such as connecting parts, soldering and testing parts, andmay be any kind of process which is carried out with respect to the partor product.

Further, the present invention is not limited to these embodiments, butvarious variations and modifications may be made without departing fromthe scope of the present invention.

As described above, according to the assembly line structure of thepresent invention, the length of the assembly line can be changedarbitrarily because the conveyer body assembly is formed by the conveyerbody units, and it is possible to cope with the change in the number ofoperation processes, the change in the product to be assembled and thelike with a high flexibility. In addition, the cost of equipment is lowbecause the present invention copes with the change in the productionplan or the like by appropriately changing the existing assembly line,and not by setting up a new assembly line from the beginning. Therefore,the present invention is extremely useful from the practical point ofview.

We claim:
 1. An assembly line for assembling a product by a series ofoperations, comprising:a conveyor body assembly including a plurality ofconveyor body units in an arbitrary number greater than or equal to twoand arranged in line, each conveyor body unit (12-1, 12-n) forming aminimal unit for carrying out a part of the series of operations andincluding an assembly area part (12-1a, 12-n) for carrying out apredetermined process for making a product to be assembled, saidassembly area part transporting an assembly jig (11) in a predetermineddirection along said line, and an assembly jig return conveyor part(12-1b,12-n) which is arranged in parallel to the assembly area part(12-1a, 12-n) and transports the assembly jig (11) used when assemblingthe product in a direction opposite to said predetermined direction. 2.The assembly line as claimed in claim 1, and further comprising astarting end traverse unit (13) which is independent from said conveyorbody assembly and transports said assembly jig from said assembly jigreturn conveyor part to said assembly jig from said assembly jig returnconveyor part to said assembly area part (12-1a, 12-n) of a respectiveconveyor body unit at a starting end of the conveyor body assembly (15),and a finishing end traverse unit (14) which is independent from saidconveyor body assembly and transports said assembly jig from saidassembly area part to said assembly jig return conveyor part of arespective conveyor body unit at a finishing end of the conveyor bodyassembly.
 3. The assembly line as claimed in claim 1, wherein a lengthof the conveyor body assembly (15) is arbitrarily set by inserting andremoving any of the conveyor body units (12-1, 12-n) from the assemblyline.
 4. The assembly line as claimed in claim 1, wherein said conveyorbody assembly provides that said series of operations are carried outwhen the product passes through the conveyor body assembly (15) once. 5.The assembly line as claimed in claim 2, wherein said conveyor bodyassembly provides that said series of operations are carried out whenthe product passes through the conveyor body assembly (15) a pluralityof times, and each traverse unit (13, 14) transports the assembly jig(11) together with the product to be assembled.